The present invention relates to a linkage and transducer assembly for sensing forces.
Various systems of linkages and transducers have been proposed to sense forces in members such as the links of the hitch for an agricultural implement. For example, U.S. Pat. No. 4,253,331 described a diamond-shaped frame with a load cell device inserted therein. Similarly, U.S. application, Ser. No. 332,577, filed Dec. 21, 1981 and assigned to the assignee of the present application, describes such a sensor system having a "snap-in" LVDT transducer. However, the "snap-in" design was expensive and difficult to manufacture and assemble due to the multiplicity of parts. For example, the separate sealing and biasing functions are performed by separate rubber boot and spring elements. Furthermore, in that design, the LVDT coil assembly is slidably received by one of the housing components and is therefore subject to wear caused by friction between the relatively movable parts. Accordingly, it would be desirable to have a simple and inexpensive "snap-in" type LVDT force sensor in which the LVDT coil assembly is protected from wear.